This invention is directed to a method and apparatus for capping bottles.
Presently existing mechanical bottle capping equipment commonly employed for capping glass bottles has not been suited for capping semirigid plastic bottles due to the inability of plastic bottles to withstand the excessive downward force exerted during the capping operation. One type of capping equipment includes a vertically reciprocating crimping head having a centrally disposed plunger mechanism which terminates at its lowermost end in a bottle cap engaging seat. This seat is surrounded by a series of crimping jaws which are in turn surrounded by a camming sleeve adapted to pivot the jaws radially inwardly against the cap skirt upon lowering the sleeve relative to the plunger mechanism.
This relative axial movement requires a substantial downwardly directed force which must be supported by the bottle when using prior art mechanically actuated bottle capping equipment. Then walled plastic beverage bottles do not have sufficient structural rigidity to counteract these forces. One approach to overcoming this problem includes molding a circumferentially enlarged ring about the bottle neck which is then used as a support during the capping operation. While the support ring arrangement is common with the larger size bottles, it has certain inherent drawbacks, particularly with the higher volume smaller size bottles such as increased weight and resin usage, handling instability and design aesthetics.
Another approach is to isolate the horizontal and vertical force components developed during the capping operation. While this can be accomplished through the use of hydraulic or pneumatic actuating mechanisms, the cost and practicality of doing so weigh heavily against it.